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AMC - Airborne Molecular Contamination

Airborne Molecular Contamination, definition and sources in the semiconductor industry

Definition of AMC

The term Airborne Molecular Contamination (AMC) intends to describe relevant characteristics of the contamination and is used to distinguish from particulate contamination:

Airborne - transport pathway of the contamination from the source to the product by convective or diffusive processes in air

Molecular - contaminant is highly diluted in the air and has no agglomerate characteristic as particles

Contamination - compound is of potential damage to the product or production tool in contact with the molecular compound

Airborne Molecular Contamination is also often referred to as “Chemical Contamination”. The later term refers to the mainly observed effects of AMC which is the chemical modification of a product surface e.g. by micro-corrosion, oxidization or change of the pH-value of a surface.

AMC is often classified and grouped in relation to the main chemical nature of the contaminating compound or its observed effect.

Typical groups are acids, bases, condensables and dopants.

However it should be noted that specific compounds can related to more than one of the above mentioned groups as their interaction with the product may depend on the product state and place of impact.

Sources for AMC

Airborne Molecular Contamination has various potential sources that can coarsly be sectioned into being located outside of the production building or clean room, and inside the clean room or production environment.

Identification of the sources for Airborne Molecular Contamination (AMC), the transport pathways and places of impact is of the highest importance for a proper and stable control of the clean production process.

The identification and quantification of the various AMC and their pathways of transport to the production environment is key to defining appropriate solutions and to reliably prevent negative effects on production.

Within the overall context of Molecular Contamination the group of Organic Compounds – in specific Volatile Organic Compounds (VOC) – gained recently much attention. Volatile Organic Compounds are present in clean production environment in a large variety. This holds true in specific for the microelectronic and semiconductor industry where significant amounts of solvents and cleaning agents are used. In many cases emissions of solvents act as precursors for AMC with severe impact to the product or production tool as e.g. in the Photolithography process of semiconductor structuring.